Port Lavaca has a humid subtropical climate with hot humid summers and mild winters. Temperatures in Port Lavaca range from an average high of 29°C (85°F) in July and August to an average low of almost 13°C (55°F) in January. Rainfall is greatest in May and June and September, peaking in September at 14 centimeters (5.5 inches) and falling to under 7.5 centimeters (three inches) from December through April. Humidity levels remain constant around 90% throughout the year. Port Lavaca has negligible snowfall.

The Light House Beach and RV site in Port Lavaca has 55 full hook-up sites. Amenities include a 670.6-meter (1200-foot) boardwalk from the beach to the bird tower, a playground and picnic area, a 464.5-square-meter (five thousand square foot) covered pavilion, a foot path that is 1.4 kilometers (almost a mile) long, and a beautiful white sandy beach. Reserved for campers are restrooms and laundry facilities. There is also a Recreation Center at Port Lavaca's Light House Beach and RV Site.

Fishing and boating are very popular pastimes in Port Lavaca. There are five fishing piers/wade-fishing areas and dozens of fishing spots in Port Lavaca. There are also 18 boat ramps and 17 kayak launch sites throughout Port Lavaca.